A high-field (7T.) fully multinuclear 89 mm. bore nuclear magnetic resonance (NMR) spectrometer is sought for use in a wide variety of biomedical research studies at the Beth Israel Hospital. These studies include studies on basic mechanism of biological function in normal and pathophysiological states, as well as studies designed to lay the groundwork for improved detection and treatment of disease. These studies include the following specific topics. (1). The transmembrane distribution of sodium and the high energy phosphate metabolism in heart will be studied during arrhythmias. (2). The intracellular potassium concentration in heart will be studied during ischemia, hypoxia, increased work loads and during cardioplegia. (3). The relaxation times, T1 and T2 of various components of the proton spectra of tumors will be studied in order to better understand the alteration relaxation values of the composite proton signal of tumors. (4). The myocardial toxicity radiographic contrast material will be investigated with respect to its effect on intracellular sodium and high-energy phosphate metabolism. (5). Ion transport and metabolism will be studied in isolated perfused kidneys, shark rectal glands and eventually suspended kidney cells. (6). Platelet membrane dynamics will be evaluated as a function of platelet function. (7). Fibrinogin will be prepared from cells in tissue culture incorporating fluorinated tyrosine and/or tryptophan. The fluorinated fibrinogin will then be utilized in order to study the mechanism of fibrin polymerization. (8). Methods of altering the relaxation parameters of blood clots using agents bearing paramagnetic centers which will localize specifically in clots will be studied. (9). Cardioplegic agents will be studied in isolated perfused hearts in order to understand the mechanisms relevant to maximum cardioplegic protection.